Cron Expression Parser
Convert crontab schedule expressions into plain English descriptions and inspect upcoming scheduled executions.
Private by architecture:
All processing is 100% client-side memory. Your data never leaves this browser tab.
Presets:
Human Readable Schedule
Loading schedule...
Next Scheduled Executions
12-Month Execution Days Calendar (2026)
Scheduled day
Idle day
Interactive Builder
Language Snippet
About This Tool
Parses crontab schedule expressions into clear plain-English summaries and calculates the next execution timestamps with second-accurate client-side evaluation.
Supports 5-part standard POSIX crontab syntax, step intervals (*/15), ranges (1-5), lists (1,15), and month/day-of-week abbreviations, plus non-standard expressions like L (last day of month).
Key Features
- Human Readable Translation: Translates complex expressions into readable English schedules.
- Next Executions Table: Calculates the next 5, 10, or 20 trigger occurrences in either UTC or local timezone.
- 12-Month Calendar Heatmap: Visually maps all scheduled days across the current calendar year.
- Multi-Language Snippets: Export ready-to-run scheduled job code for Node.js, Python APScheduler, Go robfig/cron, and AWS EventBridge.
- iCalendar (.ics) Export: Download upcoming runs as a calendar file to import directly into Apple Calendar, Google Calendar, or Outlook.
Frequently Asked Questions
What does "L" mean in the day-of-month field?
L means "last day of the month," so 59 23 L * * reads as "At 23:59 on the last day of the month."
Why do I get a warning when both day-of-month and day-of-week are set?
Standard crontab treats those two fields as an OR, not an AND: the job runs when either condition matches, which surprises people expecting both to apply together.
Where does my expression go when I click Share or Save?
Share copies a URL with the expression in the hash fragment (#expr=...), never the query string, so it is never sent to a server. Save stores it in your browser localStorage under "Saved Expressions": nothing leaves your device either way.
Which languages can I generate a code snippet for?
Node.js (node-cron), Python (APScheduler), Go (robfig/cron/v3), and AWS EventBridge/CloudWatch schedule expressions.
Can I get the schedule into my calendar app?
Yes, the .ics button exports the currently listed executions as an iCalendar file, generated entirely client-side.
Common Cron Expressions Reference
| Schedule | Cron Expression | Execution Window |
|---|---|---|
| Every 5 minutes | */5 * * * * | At minutes 0, 5, 10, ..., 55 of every hour |
| Every 15 minutes | */15 * * * * | At minutes 0, 15, 30, and 45 of every hour |
| Every hour on the hour | 0 * * * * | Minute 0 of every hour (24 runs/day) |
| Every day at midnight | 0 0 * * * | 00:00 daily |
| Weekdays at 09:00 AM | 0 9 * * 1-5 | 09:00 Monday through Friday |
| First day of every month | 0 0 1 * * | 00:00 on day 1 of each month |
| Last day of every month | 59 23 L * * | 23:59 on day 28, 29, 30, or 31 depending on month |
About This Tool
Parses a 5-field crontab expression into a plain-English schedule, lists upcoming run times, and plots every matching day across a 12-month calendar. Useful for checking schedule behavior before it goes into crontab, CI pipelines, or job schedulers.
Parses standard crontab syntax plus the L (last day) extension. Runs 100% in browser with zero server roundtrips.
Key Features
- Visual builder: Five selectors (minute, hour, day-of-month, month, day-of-week) assemble valid expressions without memorizing syntax.
- 12-month execution calendar: Every matching day of the current year highlighted across all 12 months simultaneously.
- UTC / local time toggle: Switch upcoming run times between UTC and local browser timezone.
- Copy as JSON or CSV: Export scheduled executions directly for downstream scripts or spreadsheets.
- Code snippet generator: Converts active expression into ready-to-paste snippets for Node.js, Python, Go, and AWS EventBridge.
- Quick presets: Jump quickly to common schedules like hourly, daily midnight, or weekday mornings.
Frequently Asked Questions
What does "L" mean in the day-of-month field?
L means "last day of the month," so 59 23 L * * reads as "At 23:59 on the last day of the month."
Why do I get a warning when both day-of-month and day-of-week are set?
Standard crontab treats those two fields as an OR, not an AND: the job runs when either condition matches, which surprises people expecting both to apply together.
Where does my expression go when I click Share or Save?
Share copies a URL with the expression in the hash fragment (#expr=...), never the query string, so it is never sent to a server. Save stores it in your browser localStorage under "Saved Expressions": nothing leaves your device either way.
Which languages can I generate a code snippet for?
Node.js (node-cron), Python (APScheduler), Go (robfig/cron/v3), and AWS EventBridge/CloudWatch schedule expressions.
Can I get the schedule into my calendar app?
Yes, the .ics button exports the currently listed executions as an iCalendar file, generated entirely client-side.
